Many available room temperature nematic liquid crystal materials or mixtures of these invariably belong to the substituted benzylidene aniline series as disclosed in, for example, U.S. Pat. Nos. 3,499,702 and 3,597,044. One of the major problems with anil materials is their instability to cleavage or reaction of the imine linkage. Many investigators have reported difficulties in the reproducibility of the transition of the materials by their temperature and electrooptic properties while using these materials. The nonreproducible data obtained is due, it is thought, to the generation of impurities as a result of the side reactions and decomposition of the unstable anil linkage. The other major disadvantage with the imine derivatives (Schiff bases) is their pale yellow to yellow color and this color is imparted to the electro-optic cells prepared by the use of the liquid crystals for display use and other purposes. Presence of any yellow color considerably decreases the contrast ratio of the electro-optic cells.